The treaty was seen as producing diplomatic and economic stability in western Europe after the "Second World War. Some of the main enemies during the war were now sharing production of "coal and "steel, the key-resources which previously had been central to the war effort.

The "Europe Declaration was signed by all the leaders present. It declared that the Treaty had given birth to Europe. It emphasised that the supranational principle was the foundation of the new democratic organisation of Europe. The supranational concept was opposed by "Charles de Gaulle.